This application is-based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-164695, filed May 31, 2001 the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a manufacturing method for exposure mask in semiconductor field, a generating method for mask substrate information, a mask substrate, an exposure mask, a manufacturing method for a semiconductor device and server.
2. Description of Related Art
As the semiconductor devices are miniaturized, there is a demand for micronization in the photolithographic process. Already, the device design rule is as small as 0.13 xcexcm, and the pattern dimension is about 10 nm and a very severe precision is requested. As a result, recently, problems are arising in photolithography in the semiconductor manufacturing process.
The problems are about flatness of mask substrate used in the photolithographic process as one of the factors relating to enhancement of precision in pattern forming process. That is, as the micronization is advanced, the margin for the focus in photolithography becomes smaller, and therefore the flatness of the mask substrate can be no longer ignored.
Accordingly, the present inventor accumulated studies about flatness of the mask substrate, disclosed the following.
Surface shapes of mask substrate are various, including, even in the same flatness, convex type, concave type, saddle type and mixed type. Therefore, even if the flatness is the same, when the mask substrate is fixed on the mask stage of a wafer exposure apparatus by vacuum chuck, the mask substrate may be largely deformed, or little deformed, or inversely the flatness of the mask substrate may be improved, depending on the conformity with the mask stage or vacuum chuck.
This is because the flatness of the mask substrate after chucked depends on the surface shape of the mask substrate before fixed, and also varies with the part of the mask substrate where the mask substrate is chucked by the vacuum chuck even in the same mask substrate. Depending on the surface shape of the mask substrate, the flatness of the mask substrate may be largely degraded by chucking the mask substrate on the mask stage of the wafer exposure apparatus.
It has become found that the product yield was lowered when semiconductor devices were manufactured by using an exposure mask obtained by forming a pattern on such mask substrate with low flatness.
The inventor compared the flatness of mask substrate before and after chucking the mask substrate on the mask stage of the wafer exposure apparatus, and confirmed that the flatness of the mask substrate was degraded after chucked depending on the surface shape of the mask substrate, and found that such degraded flatness was a major cause to lower the product yield.
According to a first aspect of the present invention, there is provided a manufacturing method for exposure mask comprising:
acquiring a first information showing surface shape of surface of each of a plurality of mask substrates, and a second information showing the flatness of the surface of each of mask substrates before and after chucked on a mask stage of an exposure apparatus;
forming a corresponding relation of each mask substrate, the first information and the second information;
selecting the second information showing a desired flatness among the second information of the corresponding relation, and preparing another mask substrate having the same surface shape as the surface shape indicated by the first information in the corresponding relation with the selected second information; and
forming a desired pattern on the another mask substrate.
According to a second aspect of the present invention, there is provided a manufacturing method for exposure mask comprising:
selecting a second information showing a desired flatness among the second information of relations each between a first information showing a surface shape of a surface of each of a plurality of mask substrates and the second information showing a flatness of the surface of each mask substrate before and after chucked on a mask stage of an exposure apparatus, and preparing another mask substrate having the same surface shape as the surface shape indicated by the first information in the corresponding relation with the selected second information; and
forming a desired pattern on the another mask substrate.
According to a third aspect of the present invention, there is provided a manufacturing method for exposure mask comprising:
acquiring information showing a surface shape of surface of each of a plurality of mask substrates;
forming a corresponding relation between each of the mask substrates and the information;
selecting the information showing a convex surface shape from the corresponding relation of the mask substrates, and selecting the mask substrate in the corresponding relation with the selected information from the plurality of mask substrates; and
forming a desired pattern on the selected mask substrate.
According to a fourth aspect of the present invention, there is provided a generating method for mask substrate information comprising:
acquiring a first information showing a surface shape of surface of each of a plurality mask substrates, and a second information showing a flatness of the surface of each of the mask substrates before and after chucked on a mask stage of an exposure apparatus; and
storing the first information and second information of each of the mask substrates in a corresponding relation.
According to a fifth aspect of the present invention, there is provided a generating method for mask substrate information comprising:
acquiring information showing a surface shape of a surface of each of a plurality of mask substrates; and
storing the information showing a convex surface shape of the surface of each of a plurality of mask substrates from the acquired information and a corresponding mask substrate.
According to a sixth aspect of the present invention, there is provided a mask substrate comprising:
a substrate having a surface; and
a light shielding material layer configured to cover the surface of the substrate,
wherein a surface shape of a peripheral region of the surface of the substrate is lower in height than the surface of the central portion of the surface of the substrate toward a peripheral edge of the substrate.
According to a seventh aspect of the present invention, there is provided an exposure mask comprising:
a substrate having a surface; and
a light shielding material pattern formed on the surface of the substrate,
wherein a surface shape of a peripheral region is lower in height than a surface of a central region of the surface of the substrate toward a peripheral edge of the substrate.
According to an eighth aspect of the present invention, there is provided a manufacturing method for a semiconductor device comprising:
chucking an exposure mask manufactured by a manufacturing method for exposure mask according to the above-mentioned first aspect, on a mask stage of an exposure apparatus;
illuminating the pattern formed on the exposure mask by a lighting optical system, and focusing an image of the pattern on a layer formed on a substrate by a projecting optical system; and
patterning the layer based on the image to form a corresponding pattern which forms a semiconductor device.
According to a ninth aspect of the present invention, there is provided a manufacturing method for a semiconductor device comprising:
chucking an exposure mask according to the above-mentioned seventh aspect on a mask stage of an exposure apparatus; and
illuminating the pattern formed on the exposure mask by a lighting optical system, and focusing an image of the pattern on a layer formed on a substrate by a projecting optical system; and
patterning the layer based on the image to form a corresponding pattern which forms a semiconductor device.
According to a tenth aspect of the present invention, there is provided a server comprising:
a processing device which processes storing a page including information showing a corresponding relation between a first information showing a surface shape of a surface of each of a plurality of mask substrates and the second information showing a flatness of the surface of each mask substrate before and after chucked on a mask stage of an exposure apparatus;
a processing device which processes accepting a request message corresponding to the page from a client;
a processing device which processes transmitting the page in a format displayable at the client side; and
a processing device which processes accepting an application message of the mask substrate from the client having the page transmitted.
According to an eleventh aspect of the present invention, there is provided a manufacturing method for exposure mask comprising:
acquiring a first information showing a surface shape of a surface of each of a plurality of mask substrates, and a second information showing flatness of the surface of each of mask substrates after chucked on a mask stage of an exposure apparatus obtained by simulation on the basis of flatness of the surface of each of the mask substrates measured by a flatness measuring apparatus and a structure of a mask chuck of the exposure apparatus;
forming a corresponding relation of each mask substrate, the first information and the second information;
selecting the second information showing a desired flatness among the second information of the corresponding relation, and preparing another mask substrate having the same surface shape as the surface shape indicated by the first information in the corresponding relation with the selected second information; and
forming a desired pattern on the another mask substrate.
According to a twelfth aspect of the present invention, there is provided a manufacturing method for exposure mask comprising:
selecting a second information showing a desired flatness among the second information of corresponding relations each between a first information showing a surface shape of a surface of each of a plurality of mask substrates and the second information showing flatness of the surface of each of mask substrates after chucked on a mask stage of an exposure apparatus obtained by simulation on the basis of flatness of the surface of each of the mask substrates measured by a flatness measuring apparatus and a structure of a mask chuck of the exposure apparatus, and preparing another mask substrate having the same surface shape as the surface shape indicated by the first information in the corresponding relation with the selected second information; and
forming a desired pattern on the another mask substrate.
According to a thirteenth aspect of the present invention, there is provided a manufacturing method for exposure mask comprising:
acquiring a first information showing a surface shape of a surface of a mask substrate;
acquiring a second information showing flatness of the surface of the mask substrate after chucked on a mask stage of an exposure apparatus obtained by simulation on the basis of the surface shape of the surface of the mask substrate shown by the first information and a structure of a mask chuck of the exposure apparatus;
judging whether or not the flatness of the surface of the mask substrate is conformed to a specification; and
processing the mask substrate to form an exposure mask if it is judged that the flatness is conformed.